Normal to lose a bit of brake pressure

[JLMounce]

*That's "lose" not loose*

After the event Saturday I noticed driving home that brake pressure was a little less than during the event.

THe car still stopped well but initial bite was reduced and I definitely needed to press the barke pedal in slightly more (not harder, just more) to slow the car.

I blead the brakes last night and pedal pressure returned to normal.

Obviosuly I likely got a bit of air in the lines. I'm wondering if this is something that is normal to this type of driving. Maybe my bleeders were a little loose?

Edit: Thought I would also mention that the brake fluid was flushed Friday before the event. Fluid is ATE Super Blue.

I don't think I got my brakes hot enough to boil the fluid.

[Warrtalon]

Mine feel the same way, and I had Super Blue as well, but I haven't bled mine again yet. I do believe I might have done enough to make my fluid boil considering my rotors were on fire.

[95R#177]

that's normal guys...

[JLMounce]

My brakes never got that hot. I could usually smell them a bit coming around turn 9, but they were never smokign etc. The ATE stuff has a dry boiling point a little higher than 500 degrees F. Though the pads I was using are rated from 41 to 900 degrees so I guess it's possible I could have boiled the fluid. Perhaps I should flush in some new fluid for safety sake.

[JLMounce]

that's normal guys...

ok that's good to hear then. I'll have to remember to bring a bottle with some vacuum hose to the track next time.

It's probably a good idea to bleed the system after a couple sessions then I would imagine. At least if you're running hard anyway.

[Snymo]

Yep, that's pretty normal for a track day. At the races I bleed my brakes after every single session! Other things to remember.... You will use some brake pad so by the time you go home, your pedal travel may be a little different. Topping off the brake fluid resevior can help this. Also, if you aren't using a race pad, you will probably create a glaze on the pad surface from using them so much. This can make the car feel weird on the way home. Take some really rough sandpaper to the pad surface to de-glaze them and that will help.

You may not think you are using your brakes that hard, but I guarantee you are. Stopping a 3000lb car from 100+ MPH takes a lot of work, but lap after lap will take a toll on the brakes.

Rick

[JLMounce]

You may not think you are using your brakes that hard, but I guarantee you are. Stopping a 3000lb car from 100+ MPH takes a lot of work, but lap after lap will take a toll on the brakes.

Rick

HAHA I wish my car weighed 3000 lbs. Probably closer to 3800 with fuel and 2 occupants...

Anyway good points on that. I was using Carbotech Bobcats. Quite a bit more aggressive of a compound than OE but still not a race pad.

I'll take the pads off and see if I glazed them this weekend. Thanks for the advise.

[Weston]

As Snymo mentioned, glazing tends to happen with street pads and some "performance" pads. Sometimes they also leave deposits in the rotors can cause a "warped" feeling. In my experience, 99% of the time that someone claims they have "warped rotors", it's just pad deposits that were created by getting street pads too hot.

A good race pad will not have those problems and will stop you a lot faster and handle much more heat before it fades, but you really don't want to run a race pad on the street... it'll tear up rotors and grip wont always be great at street temps. A good compromise for street and light track use is the Axxis Ultimate and Hawk HP+. Those are relatively cheap, have good bite, and can handle a little heat. I've never seen them glaze or leave deposits in rotors. True race pads will run you about twice as much, but will grip more and handle a lot more heat.

Also, if your car has ABS, you may need to bleed the ABS module itself. Definately check to see if that applies to your car or not... it is often overlooked, and it can create a big problem if neglected. In my case, the ABS module has it's own bleeder and filler, and bleeding the calipers does not affect it.

[JLMounce]

Good points.

The pads I am using are Carbotech Bobcat compounds. They're heat range is 41 F to 900 F. I didn't notice any brake fade at all during the event. Even in the later sessions when I was on the binders harder and later than in the previous sessions.

[Uli]

As Snymo mentioned, glazing tends to happen with street pads and some "performance" pads. Sometimes they also leave deposits in the rotors can cause a "warped" feeling. In my experience, 99% of the time that someone claims they have "warped rotors", it's just pad deposits that were created by getting street pads too hot.

A good race pad will not have those problems and will stop you a lot faster and handle much more heat before it fades, but you really don't want to run a race pad on the street... it'll tear up rotors and grip wont always be great at street temps. A good compromise for street and light track use is the Axxis Ultimate and Hawk HP+. Those are relatively cheap, have good bite, and can handle a little heat. I've never seen them glaze or leave deposits in rotors. True race pads will run you about twice as much, but will grip more and handle a lot more heat.

Also, if your car has ABS, you may need to bleed the ABS module itself. Definately check to see if that applies to your car or not... it is often overlooked, and it can create a big problem if neglected. In my case, the ABS module has it's own bleeder and filler, and bleeding the calipers does not affect it.
FWIW, I had HP+ leave deposits on the front rotors. For my taste they are way too loud for street use. Once they see some heat the noise goes away though. I liked them as pad for AutoX.

[MHISSTC]

I'm pretty brutal on my brakes...especially by the end of day 2. I was beginning to feel a slight pulsation on my brakes during the last session on Sunday. When I took the car off the trailer on Monday it was a definite "thump, thump, thump" on the right front like a flat-spotted tire. Upon further inspection, I found I cracked a rotor.

If you drive your car to and from the track, it's always good to take it easy enough to get back home safely. I'm glad I made the decision early on to get a trailer and tow vehicle.

Edited to add picture.
http://www.st-tel.net/~mhisstc/96COBRA/rotor.jpg